Crypto currency blows my mind.

I started investing around summer 2016. I’ve heard of bitcoin since 2015 and I thought that crypto currency is a great idea. Later I found out that there are a lot of other crypto currencies. I just got introduced to bittrex, where you can invest in lots of different crypto currencies. What I don’t understand is, what caused this currencies to change in value? Unlike normal stocks, you can mostly predict if you’ve spent your time doing your due diligent on some particular stocks. Even when it comes to commodities too. When it comes to crypto currencies, I got lost. Which one should I invest in, which one should I stay away from. The only reason these currencies go up is strictly because people are buying it - but under what reasoning? I personally put most of my money on bitcoin, followed by ripple, then steem. Steem has not been paying off for me at the moment, perhaps because its members are limited, which results in lower volume.
Perhaps what I’m looking for is if there is some kind of formula out there that can help to predict these currency prices. Something like Elliott wave that I use for commodities. Share your thoughts! Thank you!